docs: def get_configs(self):
          """
          It returns a name and a current value pairs of control files
          which are categorised in the configs group.
          """
          configs = {}
          for name, default in self.configs.items():
              cls = default.__class__
              path = self.paths[name]
              if os.path.exists(path):
                  try:
                      configs[name] = self._PARSERS[cls](fileops.read(path))
                  except IOError as e:
                      if e.errno == errno.EOPNOTSUPP:
                          # Since 3.5 memory.memsw.* are always created even if disabled.
                          # If disabled we will get EOPNOTSUPP when read or write them.
                          # See commit af36f906c0f4c2ffa0482ecdf856a33dc88ae8c5 of the kernel.
                          pass
                      else:
                          raise
          return configs